1. Field of the Invention
This invention relates to electrostatically charged sprays and more particularly to sprays for the teats and udder of cows and like milk-producing animals.
2. Description of the Art
When cows are milked it is desirable to clean and/or disinfect the teats and udder. This can be done by wiping with a cloth carrying a suitable liquid disinfectant or other chemical, as is well known. In particular it is useful to apply a chemical to prevent the bacterial infection which can occur after milking as the teat duct is then still open. One technique is to dip the teats, usually singly, into a dip-cup of chemical. This is clearly a tedious operation and errors can occur while excess chemical will drip off. A fine spray of suitable liquid may be used instead. Whatever the liquid or technique used there is a need for the accurate deposition of liquid on the teats and udder of a cow, while avoiding the deposition of the liquid elsewhere, both to avoid waste and possible pollution or adverse effects. In particular an unbroken ring of chemical around the end of the teat to exclude bacteria moving over the surface is required. It has already been proposed that electrostatically charged sprays be used, e.g. U.K. Published Patent Application 2192351A in which a flow of air is provided in addition to the spray of liquid to counter the fall-back of spray liquid from the upwardly-directed spray. However, such proposals, although providing an improvement on earlier techniques, still have problems. One problem is that the need for even a small amount of air flow is a complication.